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[Qemu-devel] [PATCH 08/10] cuda: factor out timebase-derived counter val
From: |
Mark Cave-Ayland |
Subject: |
[Qemu-devel] [PATCH 08/10] cuda: factor out timebase-derived counter value and load time |
Date: |
Sat, 3 Feb 2018 10:37:25 +0000 |
Commit b981289c49 "PPC: Cuda: Use cuda timer to expose tbfreq to guest" altered
the timer calculations from those based upon the hardware CUDA clock frequency
to those based upon the CPU timebase frequency.
In fact we can isolate the differences to 2 simple changes: one to the counter
read value and another to the counter load time. Move these changes into
separate functions so the implementation can be swapped later.
Signed-off-by: Mark Cave-Ayland <address@hidden>
---
hw/misc/macio/cuda.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/hw/misc/macio/cuda.c b/hw/misc/macio/cuda.c
index 00e71fcd5e..184d151702 100644
--- a/hw/misc/macio/cuda.c
+++ b/hw/misc/macio/cuda.c
@@ -145,21 +145,29 @@ static void cuda_update_irq(CUDAState *s)
}
}
-static uint64_t get_tb(uint64_t time, uint64_t freq)
+static uint64_t get_counter_value(CUDAState *s, CUDATimer *ti)
{
- return muldiv64(time, freq, NANOSECONDS_PER_SECOND);
+ /* Reverse of the tb calculation algorithm that Mac OS X uses on bootup */
+ uint64_t tb_diff = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
+ s->tb_frequency, NANOSECONDS_PER_SECOND) -
+ ti->load_time;
+
+ return (tb_diff * 0xBF401675E5DULL) / (s->tb_frequency << 24);
+}
+
+static uint64_t get_counter_load_time(CUDAState *s, CUDATimer *ti)
+{
+ uint64_t load_time = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
+ s->tb_frequency, NANOSECONDS_PER_SECOND);
+ return load_time;
}
static unsigned int get_counter(CUDAState *s, CUDATimer *ti)
{
int64_t d;
unsigned int counter;
- uint64_t tb_diff;
- uint64_t current_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
- /* Reverse of the tb calculation algorithm that Mac OS X uses on bootup. */
- tb_diff = get_tb(current_time, s->tb_frequency) - ti->load_time;
- d = (tb_diff * 0xBF401675E5DULL) / (s->tb_frequency << 24);
+ d = get_counter_value(s, ti);
if (ti->index == 0) {
/* the timer goes down from latch to -1 (period of latch + 2) */
@@ -178,8 +186,7 @@ static unsigned int get_counter(CUDAState *s, CUDATimer *ti)
static void set_counter(CUDAState *s, CUDATimer *ti, unsigned int val)
{
CUDA_DPRINTF("T%d.counter=%d\n", 1 + ti->index, val);
- ti->load_time = get_tb(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
- s->tb_frequency);
+ ti->load_time = get_counter_load_time(s, ti);
ti->counter_value = val;
cuda_timer_update(s, ti, ti->load_time);
}
--
2.11.0
- [Qemu-devel] [PATCH 00/10] cuda: various fixes, and move 6522 to separate device, Mark Cave-Ayland, 2018/02/03
- [Qemu-devel] [PATCH 03/10] cuda: don't call cuda_update() when writing to ACR register, Mark Cave-Ayland, 2018/02/03
- [Qemu-devel] [PATCH 07/10] cuda: set timer 1 frequency property to CUDA_TIMER_FREQ, Mark Cave-Ayland, 2018/02/03
- [Qemu-devel] [PATCH 01/10] cuda: do not use old_mmio accesses, Mark Cave-Ayland, 2018/02/03
- [Qemu-devel] [PATCH 02/10] cuda: don't allow writes to port output pins, Mark Cave-Ayland, 2018/02/03
- [Qemu-devel] [PATCH 08/10] cuda: factor out timebase-derived counter value and load time,
Mark Cave-Ayland <=
- [Qemu-devel] [PATCH 04/10] cuda: introduce CUDAState parameter to get_counter(), Mark Cave-Ayland, 2018/02/03
- [Qemu-devel] [PATCH 06/10] cuda: minor cosmetic tidy-ups to get_next_irq_time(), Mark Cave-Ayland, 2018/02/03
- [Qemu-devel] [PATCH 05/10] cuda: rename frequency property to tb_frequency, Mark Cave-Ayland, 2018/02/03
- [Qemu-devel] [PATCH 09/10] misc: introduce new mos6522 VIA device and enable it for ppc builds, Mark Cave-Ayland, 2018/02/03
- [Qemu-devel] [PATCH 10/10] cuda: convert to use the shared mos6522 device, Mark Cave-Ayland, 2018/02/03